Measurement of the production cross section for Zγ → ννγ in pp collisions at √s =7 TeV and limits on ZZγ and Zγγ triple gauge boson couplings

Abstract

A measurement of the Zγ → ννγ cross section in pp collisions at √ s = 7 TeV is presented, using data corresponding to an integrated luminosity of 5.0 fb−1 collected with the CMS detector. This measurement is based on the observation of events with an imbalance of transverse energy in excess of 130 GeV and a single photon in the absolute pseudorapidity range |η| < 1.4 with transverse energy above 145 GeV. The Zγ → ννγ production cross section is measured to be 21.1±4.2 (stat.)±4.3 (syst.)±0.5 (lum.) fb, which agrees with the standard model prediction of 21.9 ± 1.1 fb. The results are combined with the CMS measurement of Zγ production in the ` +` −γ final state (where ` is an electron or a muon) to yield the most stringent limits to date on triple gauge boson couplings: |h Z 3 | < 2.7 × 10−3 , |h Z 4 | < 1.3 × 10−5 for ZZγ and |h γ 3 | < 2.9 × 10−3 , |h γ 4 | < 1.5 × 10−5 for Zγγ couplings.